As far as we are aware, no chemical compounds which have a 3-carboxy-2-azabicyclo[2.2.1]heptane nucleus have been previously reported to have any biological activity.
Most of the related compounds described in the prior art were prepared to study certain chemical reactions, especially, the Diels-Alder addition reaction used to form such cyclic compounds.
For example, M. S. Roasch, J. Org. Chem. 40 161 (1979), describes the use of 2-(p-toluenesulfonyl)-2-azabicyclo[2.2.1]hept-5-ene-exo-3-carboxylic acid. This compound has a double bond in the azabicycloheptane ring and a difficulty removable tosyl group at the N-ring member. A. J. G. Baxter et al., J. Chem. Soc. Perkins I, 2343 (1977), describes the preparation of azabicyclo[2.2.2]octenes using the Diels-Alder reaction with an iminoacetate and cyclohexadiene. G. R. Krow et al., Tetrahedron Letters 23 1971 (1978), describes the similar preparation of 3-carbethoxy-2-carbobenzyloxy-2-azabicyclo-[2.2.2]oct-5-enes.
J. M. Biehler et al., Tetrahedron, 3171 (1971), describes certain 2-azabicyclo[2.2.1]heptanes which have two carboxylic acid functions, such as cyano or carboxamido, at the 3-position. M. E. Jung et al., Tetrahedron Letters 22 4607 (1981), discloses the preparation of a number of 2-carboalkoxy-3-carbethoxy-2-azabicyclo[2.2.1]heptenes. This publication was received in the United States on Nov. 19, 1981, well after our reduction-to-practice of the invention described hereafter.